Packing for stuffing-boxes of pistons



C. MCBURNEY.

Rubber Fabrics.

No. 24,569. Patented June 28, 1859.

Wv-n/esses jnvenior UNITED STATES PATENT OFFICE.

CHARLES MCBURNEY, OF ROXBURY, MASSACHUSETTS.

PACKING FOR STUFFING-IBOXES OF PISTONS.

Specification of Letters Patent. No. 24,569, dated June 28, 1859.

To all whom it may concern:

le it known that I, CHARLES MCBURNEY, of Roxbury, in the county ofNorfolk and State of Massachusetts, have invented a new and usefulPacking for the Stuffing-Boxes of Piston and Valve Iods, of which thefollowing is a full, clear, and exact description, reference being hadto the accompanying drawings, making part of this specification, inwhich- Figure l is a plan of the packing in the sheet; Fig. 2, a stripas it is bent into a circle when it is in use; Fig. 3, a section througha stuffing box with the packing inserted.

The hempen packing heretofore employed in stufling boxes is not easilyadjusted so as to produce a uniform pressure upon all sides of the rod,and an elastic, durable substitute for it has long been a desideratum.In experimenting for this purpose I have laid together a suitable numberof plies of canvas or cotton cloth with india rubber between themforming a cake of packing which was afterward cut into strips. This wasfound to be objectionable for three reasons-First, the longitudinalthreads of the canvas rendered the strips ot' packing very difficult tobend so as to insert it into the stuffing box; second, the shorttransverse threads prevented the packing from yielding with sufficientease when the follower was brought down upon it; third, the longitudinalthreads of the strip were drawn out of place by the motion of the rod,leaving the packing with an uneven surface. The same packing was thencut into rings, the inner circle of which was of the diameter of the rodand the other circle of a diameter ust sufficient to fill the stuffingbox. but it is obvious that this method of cutting the packing is verywasteful of 1na terial. as each stuffing box requires a ring of aparticular size both upon its inner and outer circle and as the ends ofthe threads are exposed to wear at four points around the circle whileat the four intermediate points the sides of the threads are exposed,these rings wear very irregularly and when worn they become useless.

To remove all these objections is the object of my present invention thenature of which I will now proceed lto describe.

I take 25 lbs. of india rubber', 2 lbs. sulfur, 4 to 8 lbs. of silica,or plumbago with this compound after it is suitably ground and mixed,canvas or other suitable fabric of cotton linen or hemp is coated uponeach side,

anda sutlicient number of plies of such fabric are united by a heavypressure or by rolling. The packing is then vulcanizedand to prepareitfor use it is cut diagonally into strips (as seen in Fig. l.) Thesestrips are then cut of the right length and are bent into rings (Fig.2.) which are inserted into the stuffing box as seen in Fig. 3 in whichA is the box; B, the follower; C, the packing; D, the valve or pistonrod.

In lieu of cutting the packing into short strips, and bending it intorings as above described, a longer strip may be wound spirally aroundthe rod, the pressure of the follower bringing it to a uniform bearingupon the rod. It will be observed that when cut diagonally as abovedescribed the ends onlyof all the threads are exposed to wear by whichit is caused to wear slowly and uniformly while there are nolongitudinal threads to resist the action of bending the strips and theyare. consequently easily coiled within the stuffing box. Also as thereare no threads running transversely of the packing it is easily causedto expand against the rod by pressure and thus as the packing wears itmay be again and again tightened up by bringing down the follower.

In lieu of making the packing of continuous strips of canvas, the lattermay be cut into lozenge shaped pieces Fig. 4 which when matched together(F ig. 5) may be cut longitudinally as upon the line y, y, and producethe same effect.

The compound which I have given above is that which I prefer for themanufacture of the packing but both the ingredients and the proportionsin which they are used may be variously modified without altering thespirit of my invention. Even the vulcanizing process may be dispensedwith and I do not therefore restrict myself thereto; but

Then I claim as my invention and desire to secure by Letters Patent is-A packing for stuffing boxes composed of canvas and india rubber as setforth and cut diagonally as described.

CHAS. MCBURNEY.

lVitnesses THos. R. RoAcH, SAM. COOPER.

